Photos: Last U.S. troops leave Iraq

Boot footprints are seen in front of U.S. Mine Resistant Ambush Protected (MRAP) vehicles in the nearly deserted Camp Adder, now known as Imam Ali Base, on December 16.

Boot footprints are seen in front of U.S. Mine Resistant Ambush Protected (MRAP) vehicles in the nearly deserted Camp Adder, now known as Imam Ali Base, on December 16.